TY - JOUR

T1 - Full-field strain evolution during intermartensitic transformations in single-crystal NiFeGa

AU - Efstathiou, C.

AU - Sehitoglu, H.

AU - Carroll, J.

AU - Lambros, J.

AU - Maier, H. J.

N1 - Funding Information: This work was partially supported by the Fracture Control Program, the Midwest Structural Sciences Center (MSSC), and the National Science Foundation CMS-0428428. The MSSC is supported by the US Air Force Research Laboratory Air Vehicles Directorate under contract number FA8650-06-2-3620. The single-crystals were obtained from Prof. Yuri Chumlyakov, Tomsk State University, Russia.

PY - 2008/9

Y1 - 2008/9

N2 - Using in situ digital image correlation to obtain full-field measurements, we study the intermartensitic transformations in single-crystal NiFeGa. Full-field strain measurements identify the coexistence of modulated martensite phases during the first plateau of the multistage stress-strain curve at room temperature. At a higher temperature, the measurements indicate the bypassing of one of the modulated phases. Strain as high as 13% is measured as a result of the transformation to the intermediate monoclinic modulated and final tetragonal phase. Based on the full-field strain measurements, the phase fractions during the nucleation and the progression of the transformation are obtained. The evolution of the local strain and the phase fractions prove critical in explaining strain softening, hysteresis and other phenomena observed in the stress-strain curves.

AB - Using in situ digital image correlation to obtain full-field measurements, we study the intermartensitic transformations in single-crystal NiFeGa. Full-field strain measurements identify the coexistence of modulated martensite phases during the first plateau of the multistage stress-strain curve at room temperature. At a higher temperature, the measurements indicate the bypassing of one of the modulated phases. Strain as high as 13% is measured as a result of the transformation to the intermediate monoclinic modulated and final tetragonal phase. Based on the full-field strain measurements, the phase fractions during the nucleation and the progression of the transformation are obtained. The evolution of the local strain and the phase fractions prove critical in explaining strain softening, hysteresis and other phenomena observed in the stress-strain curves.

KW - Digital image correlation

KW - Martensitic transformation

KW - Metastable phases

KW - Nucleation of phase transformations

KW - Shape memory alloy (SMA)

UR - http://www.scopus.com/inward/record.url?scp=48449097711&partnerID=8YFLogxK

U2 - 10.1016/j.actamat.2008.04.033

DO - 10.1016/j.actamat.2008.04.033

M3 - Article

AN - SCOPUS:48449097711

VL - 56

SP - 3791

EP - 3799

JO - Acta materialia

JF - Acta materialia

SN - 1359-6454

IS - 15

ER -